linux-kernel - Re: [PATCH] drivers/media/video: avoid NULL dereference

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 22 Mar 2010 23:14:41 -0400
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Julia Lawall <julia@...u.dk>
Cc:	Mark McClelland <mmcclell@...foot.com>,
	Mauro Carvalho Chehab <mchehab@...radead.org>,
	linux-usb@...r.kernel.org, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] drivers/media/video: avoid NULL dereference

On Sun, 21 Mar 2010 22:31:06 +0100 (CET) Julia Lawall <julia@...u.dk> wrote:

> From: Julia Lawall <julia@...u.dk>
> 
> If ov is NULL, it will not be possible to take the lock in the first place,
> so move the test up earlier.
> 
> ...
>
> --- a/drivers/media/video/ov511.c
> +++ b/drivers/media/video/ov511.c
> @@ -5913,14 +5913,12 @@ ov51x_disconnect(struct usb_interface *intf)
>  
>  	PDEBUG(3, "");
>  
> +	if (!ov)
> +		return;
> +
>  	mutex_lock(&ov->lock);
>  	usb_set_intfdata (intf, NULL);
>  
> -	if (!ov) {
> -		mutex_unlock(&ov->lock);
> -		return;
> -	}
> -
>  	/* Free device number */
>  	ov511_devused &= ~(1 << ov->nr);

I think we can pretty safely assume that we never get here with ov==NULL.

Oh well, I'll leave the test there for others to ponder.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/